1. Field of the Invention
The invention relates to a method for operating an apparatus with fuel cells wherein the method includes a start-up phase and a current-delivering operating state as well as to an apparatus with which the method can be carried out.
2. Description of the Prior Art
A prereformer is integrated into an apparatus of this kind which is known from EP-A 0654 838. During the start-up phase, an auxiliary burner is used to heat up the prereformer on the one hand and the infed air is preheated in a channel system in the jacket on the other hand. Heat is supplied to the cell block with the preheated air. This supply of heat is not sufficient to heat the fuel cells to a minimum operating temperature of 850.degree. C. It is therefore necessary to feed combustion gas and air into the apparatus and allow it to burn in the afterburner chamber between the cell block and the jacket. Immediately after the beginning of the combustion, which must be ignited, large temperature gradients arise, through which the cells can be damaged.